The present invention relates generally to a device for cleaning the fuel injection system of an engine and measuring flow through the individual injectors, and in particular to a fuel injector cleaner and injector flow measurement device for the engine of an automotive vehicle.
Fuel injected engines offer more performance, better mileage, and reduced exhaust emissions. These advantages are not without some disadvantages as fuel injectors are relatively expensive and sensitive both to fuel quality and fuel contamination. Further, fuel injectors are apt to gradually acquire deposits restricting the area of the fuel passage, which deposits can effect the fuel spray and thus the engine performance. It is typically not practicable to disassemble and discard expensive parts because of fuel quality or fuel contamination problems.
Most major fuel producers have developed additives for their fuels that contain solvents and detergents to prevent deposit accumulation. This will not solve the problem with vehicles in which deposits were already present. Further, many of the independent fuel producers do not include additives due to the increased expense. Customers are prone to use less expensive fuels, especially in older vehicles that are out of warranty. Most of these cheaper fuels do not contain sufficient additives to be effective.
To remove these deposits, apparatus has been proposed to clean the fuel injection system. Illustrative is GB 2117048, published Oct. 5, 1983, the specification being specifically incorporated herein by reference. GB 2117048 disclose that a chemical additive is added to a separate tank which is connected to and forms the fuel source for the vehicle engine. The chemical is mixed and pressure fed to the fuel injector system in substitution for the regular vehicle fuel supply. Thus the engine runs on the cleaning fluid gas mixture. However, residue and foreign material removed from the carbon covered surfaces are not necessarily removed from the system. If not completely removed, such residual particles contaminate the system and eventually return to the fuel tank for deposit therein. For example, excess fuel passed through the fuel rail and not used by the injectors is returned to the tank. The above problems create a need for equipment to remove deposits and restore engine fuel injection system performance.
Accordingly, it is an important object of the present invention to provide a carbon-cleaning apparatus for fuel injected engines that solve the aforementioned problems.
Another object of the invention is to provide a carbon-cleaning device for in situ cleaning of the injection valves of vehicle engines.
Another object of the invention is to provide a dynamic flow measurement device and method for each individual injector without removing any of the injectors from the engine, the flow device being integrated into the same device that cleans the injectors and utilizing most of the same components of such device.
Another object is provision of apparatus having pump means separate from the vehicle and a control therefor whereby the pump both feeds and extracts the cleaning fluid from the vehicle's fuel pumping system.
Another object is provision of apparatus having sensor means for sensing an excessive pressure drop across a filter thereby warning that the system filter is contaminated and should be changed.
Another object is provision of apparatus having means for pulsing the individual injectors during flow testing thereby simulating different engine operating conditions.
According to the present invention there is provided an apparatus for cleaning and/or testing the fuel injection system of a vehicle engine, and a method for each. The engine valve system is of the type including at least one fuel injector operably secured to and associated with the engine, fuel supplying means, including an engine pump, for supplying fuel to the fuel injector, injector controlling means for controlling the operation of the fuel injectors whereby to feed fuel to the engine cylinders associated with the injectors, and power means for powering the controlling means.
The cleaner apparatus in accordance with this invention comprises pump means separate and apart from the vehicle for feeding fuel into the fuel supplying means, control means for controlling the pump means, including means for operating said at least one fuel injector while said injector is disposed in operable association with said vehicle engine and means for operating the pump in a fuel feeding mode and in a fuel withdrawing mode whereby to retract fuel from the system, and means for operably associating said pump means with said fuel supplying means and disabling said fuel supplying means to permit said pump means to be the sole source of the fuel supply for said at least one fuel injector. Further, the apparatus comprises flow measuring means for measuring the flow of fuel through each injection valve during the operation of the injection valve and while the injection valve is operably secured to and associated with said engine, and pulse means for controlling the duration of fuel flow through each injection valve.
Advantageously, removal of the cleaning fluid from the vehicle engine eliminates or reduces the cleaning fluids contacted with those vehicle components which are likely to be corroded, recompounded, or otherwise corrupted by the cleaning fluid.
Advantageously, indication of a low system pressure signals the operator that the fuel mixture may be contaminated and to take corrective action whereby to prevent reintroduction of contaminants into the injectors.
Advantageously, alteration of the injector operating pulse allows the fuel injectors to be operated and tested over the full engine operational range and affords more realistic cleaning and testing under conditions more closely approximating real operating conditions.
Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from the subsequent description of the preferred embodiments and the appended claims taken in conjunction with the accompanying drawings.